1. Technical Field
The present invention generally relates to containers for storing fragile food products, and more particularly, to a blow molded container for storing potato chips and/or crisps, corn based chips and/or crisps, cookies and the like which is capable of adapting to changing environmental conditions while maintaining its visual aesthetic appearance.
2. Description of the Related Art
There are presently a great number of containers known for the storage of fragile food products (e.g., snack chips, crisps, cookies and the like). Inherent in every container's design is the requirement to compensate for or adapt to changing environmental conditions. Changes in environmental conditions (i.e., temperature, pressure and humidity) are a natural consequence of manufacturing processes. For example, dry food products are typically manufactured at elevated temperatures and thereafter hermetically sealed to protect the product from spoiling. Once sealed, a certain amount of gas is trapped within the container. As the contents of the hermetically sealed package cool to an ambient temperature, a partial vacuum is created which may cause the container to implode, distort or destroy the seal.
Changes in atmospheric pressure also affect the volume of gas trapped within a container. This is normally not a problem for dry food products because they are typically packaged in flexible packages (e.g., bags and flexible film overwraps) that can adjust their shape to changing environmental conditions. However, flexible packages offer little, if any, protection from outside physical forces to the contained fragile food products. Thus, increasingly, a need to use more rigid containers has arisen.
While rigid containers constructed of paper and foil are well known in the art, their utilization in packaging fragile food products presents many inherent drawbacks. The manufacturing costs of such rigid containers are relatively high. Moreover, in order to provide enough strength to resist forces induced by environmental change, the weight of such containers is relatively high. Additionally, changes in humidity can adversely affect the structural integrity of such containers.
Containers constructed of thermo-plastic substances are increasingly gaining in popularity for packaging fragile food products. However, packaging fragile dry food products utilizing current thermo-plastic container technology is still problematic. While previous efforts have addressed the problems associated with utilizing thermo-plastic containers in packaging liquid products, these efforts have not addressed the inherent problems associated with packaging fragile dry food products. Fragile dry food products (e.g., snack foods, baked goods and cereals) contain significantly larger amounts of entrapped gas, both within their structure as well as in their surrounding packaging, than do liquid products. The effect environmental changes impart on this larger volume of entrapped gas profoundly affects the packaging requirements of fragile dry food products. Currently, thermo-plastic technology offers two basic alternatives for manufacturing plastic containers that adapt to or compensate for changing environmental conditions.
First, by increasing the thickness of the container's sidewall, a thermo-plastic container may be fashioned which is strong enough to resist forces induced by changing environmental conditions. However, such containers are generally undesirable in that they are expensive, in terms of materials, to manufacture and their weight is relatively high. Moreover, they are less environmentally friendly in that their ability to biodegrade is generally more protracted than thinner walled containers.
Alternatively, the thickness of a container's sidewall may be reduced so as to fashion a thermo-plastic container capable of adjusting its shape to changes in environmental conditions like a flexible package, but being sufficiently rigid to offer some protection from outside physical forces. However, such containers have significant commercial drawbacks. While it is currently possible to fashion a relatively thin walled thermo-plastic container that is capable of withstanding expansion forces resulting when the container's interior pressure is greater than the ambient pressure; such thin walled thermo-plastic containers tend to buckle, deform, or implode in a generally unpredictable manner when the interior pressure is less than the ambient pressure (e.g., the vacuum inducing manufacturing process discussed previously). Such deformation or implosion tends to detract from the commercial presentation of the container and often is interpreted as a damaged or defective product by purchasing consumers.
A variety of proposals have previously been made to circumvent the problems inherent in designing thermo-plastic containers capable of adapting to environmental changes. For Example, U.S. Pat. No. 6,074,677 to Croft discloses a composite food container comprised of a vacuum packed inner flexible bag 60 and a rigid plastic tubular outer container 20. While the rigid plastic outer container 20 protects the container's contents, the differential between the vacuum in the inner flexible bag 60 and the vacuum in the region R between the inner bag and the outer container is sufficiently maintained so as to prevent the spoilage of the food product within the inner bag 60. However, such a container is both complicated and relatively expensive to manufacture.
Another prior proposal is U.S. Pat. No. 5,921,429 to Gruenbacher et al. which discloses a substantially rectangular plastic container for multiple, side-by-side stacks of fragile food articles comprised of a single blow molded body. Key to the Gruenbacher et al. '429's design is the inclusion of an internal partition 16 having two spaced apart walls 26 and 28 which are adapted to deform in the presence of vacuum and pressure in the compartments such that the outer perimeter dimension of the container remains substantially the same and the wrap around labeling retains its fit. In addition to requiring a relatively complicated manufacturing process, the Gruenbacher et al. '429 design is not suited to packaging a single stack of fragile food articles.
A need, therefore, exists for an improved blow molded thermoplastic container which is relatively simple to manufacture and strong enough to resist external compressive force, yet capable of adapting to changes in environmental conditions without adversely impacting the commercial presentation of the container.